Search PubMed⌕ Search

Biomedical subjects

I Cohen

Publications and source records attributed to I Cohen.

496 records · Page 28Linked to original sources
PubMedDate not supplied

Effects of intravenous test dose epinephrine on fetal sheep during acute fetal stress and acidosis.

Small IV doses of epinephrine (epi; 5.0-20.0 micrograms), similar to those advocated for epidural test dosing, cause a significant though transient (3 minutes) reduction in uterine blood flow in pregnant ewes but no subsequent adverse effect on the mature, unstressed fetus. The purpose of this study was to investigate the acute effects on the mature fetus of a maternal IV test dose of 12.5 mg bupivacaine and 50.0 micrograms fentanyl with or without 16.5 micrograms epi in the presence of acute placental insufficiency and fetal asphyxia. Two minutes after dosing and for 15 minutes thereafter, no changes were observed in maternal heart rate (HR), mean arterial pressure (MAP) or arterial blood gas values and catecholamine concentrations other than a statistically significant doubling in epi levels after epi dosing. Mildly (mean arterial pH, 7.23) and severely (mean pH, 6.87) acidotic fetuses differed with respect to arterial pO2, pCO2 and catecholamine values, but in neither group were any changes observed after maternal dosing. Under the conditions of acute fetal stress and acidosis produced in this experiment, inclusion of epi 16.5 micrograms in an epidural test dose does not significantly affect the HR, MAP, aortic flow, blood gases or catecholamine levels of the mature fetal sheep when injected intravenously.

Acidosis↗
PubMedDate not supplied

[Chronic hemodialysis: risk factors for intra-dialytic hypotension (IDH)].

Haemodialysis is the most used among the different renal function replacement methods. Although the survival is acceptable the mobility is important; intradialytic hypotension is a main cause of such mobility. In this study which included stable chronic haemodialysis patients, the authors evaluate risk factors for IDH. Advanced age, female sex and autonomic insufficiency are risk factors for IDH. Patients with IDH had more serious ventricular arrhythmias, but a cause-effect relationship was not demonstrated.

Aged↗
PubMedDate not supplied

Platelet structure and function role of prostaglandins.

A long way has been travelled since platelets were likened to sponges in 1961. At that time research on thrombotic mechanisms was mainly concentrated on blood coagulation. Since then, a shift of emphasis toward the study of platelets has dramatically evolved. How to prevent platelets from becoming sticky at sites of injury has been the main concern for platelet researchers over the past decade. Following adherence of platelets to a damaged vessel wall, prostaglandin synthesis is triggered leading to the formation of thromboxane A2, the most potent platelet activating agent so far discovered. By an "autocatalytic" process, thromboxane A2 together with the released ADP are responsible for the growth of the platelet thrombus. Among the substances released by the alpha-granules is the mitogenic factor, which, by stimulating the proliferation of smooth muscle cells from the media to intimal layers in arteries, is instrumental in the generation of atherosclerotic plaques. The narrowing of the vessel wall lumen can be further aggravated by the formation of a thrombus over the plaque, thereby occluding the vessel, and leading to cardiovascular diseases or stroke depending on the location of the lesion. An all-out effort to find a means for preventing platelet stickiness is currently under way. The recent discovery of prostacyclin has been the cornerstone for most of the research carried out so far in this field. The presently available antiplatelet drugs should be used with caution. Indeed, whereas a dramatic thrombosis may occur with full platelet activation, a catastrophic hemorrhage may follow the "neutralization" of platelets. Eskimos who are fed with eicosapentaenoic acid, the precursor of a potent antiplatelet agent, may indeed be immune against thrombotic disorders; however, they have an increased tendency to bleed.

Aspirin↗
PubMedDate not supplied

Prolonged survival of allogeneic mouse skin grafts following preservation.

Skin of C57BL mice was preserved in skin-graft fluid at 4 C for six weeks. The mean survival time of such skin grafted to BALB/c mice was 17.1 +/- 0.29 (SD) days. Control grafts transplanted immediately after removal from animals had a mean survival time of 11.5 +/- 0.32 days, whereas in a second control group, transplanted with C57BL skin preserved up to two weeks in serum-free medium, rejection occurred after 10.9 +/- 0.16 days. Some hypotheses on the mechanism of such graft prolongation are discussed.

Animals↗